The purpose of this report is to investigate the potential application of voice recognition and speech synthesis to a wearable computer for use by dismounted soldiers. A literature review was conducted to identify the issues and capabilities of voice controls and displays for dismounted infantry soldiers. Current applications of voice interfaces are identified including the Force XXI modified Land Warrior user voice control system. Considerations regarding the appropriate use of speech input and voice displays are discussed including use of speech as opposed to tonal or visual displays, text-to-speech synthesis, types of speech displays and speech display intelligibility. Factors influencing the effectiveness of speech input and voice control systems are described including speaker dependence, word boundaries, vocabulary size, and system performance. Environmental factors affecting speech recognition accuracy are discussed including ambient noise, vibration, and operator stress. Finally, this report considers general system design issues including speech input device activation and deactivation, multi-modal displays and controls, feedback and error correction, vocabulary size and selection, robustness to ambient noise, system size, microphone and headset design, compatibility with masks and exclusion garments, training, and security issues.